In 2046, many aspects of life are carried out on a virtual network. No matter how advanced the time becomes, however, bullying never disappears. Haruyuki is one of the bullied students. However, one day he is contacted by Kuroyukihime, the most famous person in the school. "Wouldn't you like to 'accelerate' and go further ahead, boy?" Haruyuki is introduced to the "Accel World" and decides to fight as Kuroyukihime's knight.
Nega Nebulus investigates a disturbance in the Accelerated World which is also having negative effects on the real world, and is forced to team up with the other Kings to combat the threat.